Both DVI connections are dual link - one I one D.... Don't know what that really means - it seems the cables I was using, which are DVI-D can work with either the DVI-D or DVI-I plugs... Anyways, I did find out what the issues was, which was not related to the video cars, cable or connectors.
As it turns out, the ASUS monitors that I purchased had a "human sensor" i.e. they turn off when they do not sense a human/motion in front of them. With three monitors the right two, and especially the right one was always turning off. This also explains why when I hit the desk they would click back on. Anyways, now that I have turned off that ridiculous function - all is well.
In the end, I have gone with what you suggested as it will also allow me to get my older 4th auxillary monitor working was well.
Thanks for the suggestions.